I have only used THY for one round trip LGW/IST/JNB then CPT/IST/LGW in 2016.
The flights in C were all fine. The service on the ground in IST was so abominable, that I shall never use that airline or IST again. Indeed, the whole country can rejoice that I have zero intention of ever going there.
I respectfully suggest that the new thread title is correct!